
#include <stdio.h>

int invSqrt(float x)
{
	int i = *(int *) &x;
	i = 1597463007 - (i >> 1);
	x = * (float *) &i;
	return x;
}

int main(void)
{
	float num = 0.0625;
	float f = invSqrt(num);
	printf("the reciprocal square of %f is %f \n", num, f);
	return 0;
}